In this article, we detail how to produce two inexpensive micromanipulators that offer high precision (approximately 25 micrometers) along a single axis of movement. The more expensive of the designs provides improved versatility along multiple axes. Both manipulators offer substantial savings over commercially available micromanipulators with comparable capabilities. Plans and instructions are given such that a novice can produce the manipulators with simple tools. The manipulators are designed to serve undergraduate teaching exercises in physiology. An electroretinogram exercise is suggested in adult house flies ("Musca") or flesh flies ("Neobellieria"). Measuring the intensity-response function and temporal characteristics of visual transduction are discussed. A brief introduction to the field of visual transduction and the physiology of the laboratory exercises is provided as well.